In U.S. Pat. No. 4,219,559 there are described a number of 1-substituted N-heterocyclyl-4-piperidinamines as compounds having useful anti-histaminic properties.
In U.S. Pat. Nos. 4,556,660, 4,634,704, 4,695,569 and 4,588,722 there are described further series of N-heterocyclyl-4-piperidinamines as compounds having useful anti-histaminic and serotonin-antagonistic properties.
Further there are described in the Eur. Pat. Publ. No. 151,826 published Aug. 21, 1985, which corresponds to U.S. Ser. No. 671,135 a number of 4-(bicyclic heterocyclyl)methyl and -heteropiperidines having useful anti-histaminic and serotonin-antagonistic properties. In addition some anti-histaminic (4-piperidinylmethyl and -hetero)purines have been described in the Eur. Pat. Publ. No. 206,415 published Dec. 30, 1986, which corresponds to U.S. Ser. No. 858,339.
Finally, some anti-histaminic N-1H-benzimidazole-4-piperidinamines have been described in J. Heterocyclic Chem., 24, 31 (1987).
The compounds of the present invention differ therefrom by the fact that the benzimidazole derivative is invariably substituted in the 1-position with a hydroxy-, mercapto- or amino-C.sub.1-6 alkyl group, which is optionally O, S or N-alkylated, and by their favourable pharmacological properties.